Analytical model for compressive arch action in horizontally restrained beam-column subassemblages

This paper presents an analytical model to predict the compressive arch action (CAA) of reinforced concrete beam-column subassemblages. In the model, a new method is proposed to quantify the strains of longitudinal reinforcement in the beam. Instead of equivalent rectangular concrete stress block, the constitutive model for concrete is employed to calculate the compression force sustained by concrete. Besides, tensile strength of engineered cementitious composites can also be considered. Comparisons between experimental and analytical results indicate that the model yields reasonable accuracy in predicting the CAA capacity and horizontal compression force of subassemblages. The effects of horizontal restraints on the CAA capacity of subassemblages are also investigated through the model. Furthermore, pseudo-static resistance of beam-column subassemblages is calculated based on the energy balance method. Finally, conclusions on the enhancement of CAA to structural resistance are drawn from analytical results.